<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>abcd</title>
  </head>
  <body bgcolor="#FFFFFF">
    <center>Scilab Function</center>
    <div align="right">Last update : April 1993</div>
    <p>
      <b>abcd</b> -  state-space matrices</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>[A,B,C,D]=abcd(sl)  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>sl</b>
        </tt>: linear system (<tt>
          <b>syslin</b>
        </tt> list) in state-space or transfer form</li>
      <li>
        <tt>
          <b>A,B,C,D</b>
        </tt>: real matrices of appropriate dimensions</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    returns the <tt>
        <b>A,B,C,D</b>
      </tt> matrices from a linear system <tt>
        <b>Sl</b>
      </tt>.</p>
    <p>
    Utility function. For transfer matrices <tt>
        <b>Sl</b>
      </tt> is converted
    into state-space form by <tt>
        <b>tf2ss</b>
      </tt>.</p>
    <p>
    The matrices <tt>
        <b>A,B,C,D</b>
      </tt> are the elements <tt>
        <b>2</b>
      </tt> to <tt>
        <b>5</b>
      </tt> of
    the <tt>
        <b>syslin</b>
      </tt> list <tt>
        <b>Sl</b>
      </tt>, i.e. <tt>
        <b>[A,B,C,D] = Sl(2:5)</b>
      </tt> .</p>
    <h3>
      <font color="blue">Examples</font>
    </h3>
    <pre>

A=diag([1,2,3]);B=[1;1;1];C=[2,2,2];
sys=syslin('c',A,B,C);
sys("A")
sys("C")
[A1,B1,C1,D1]=abcd(sys);
A1
systf=ss2tf(sys);
[a,b,c,d]=abcd(systf)
spec(a)
c*b-C*B
c*a*b-C*A*B
 
  </pre>
    <h3>
      <font color="blue">See Also</font>
    </h3>
    <p>
      <a href="../elementary/syslin.htm">
        <tt>
          <b>syslin</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="../elementary/ssrand.htm">
        <tt>
          <b>ssrand</b>
        </tt>
      </a>,&nbsp;&nbsp;</p>
  </body>
</html>
